Quote:
Originally Posted by businessdude
Hmm - never heard the term before but interesting. So you are saying just the possibility of interference exists, not that it happens on every stroke right? So if you get interference, what exactly happens? At max compression when piston is pushed up to its highest point, both valves are closed, so then somehow the piston causes a valve(s) to open? Then it's a major problem and you need a timing belt adjustment?
The
possibility for interference exists on every stroke. But it should never happen. If it does, bad things will result.
When the valves open, to allow air/fuel into the chamber or to allow exhaust to escape, they physically occupy space that will
interfere with the piston when it reaches the top of the chamber. That's why precise timing is involved.
If a timing belt breaks, the valves are no longer being controlled by the camshaft so will often remain in whatever position they were in at the time of the break. Inevitably, some will be open and will
interfere with the piston. At best, you'll only have bent/broken valves. Very often, add broken piston(s) to that. Worst case, the head (where the valves reside) is damaged and/or parts explode through the block and/or head. A broken timing belt is usually a death sentence for an engine, particularly when under load (high rpm's).